revolution." No statement has ever seemed more true today as older workers approach retirement, but aren't ready to stop working. Rather, they want to revitalize their careers.

This growing trend isn't limited to boomers staying in the work force. It encompasses women returning to work after maternity leave, workers wanting to change careers in general, even those who are sick of retirement and just want to make a comeback.

To Marc Freedman, author of "Encore: Finding Work That Matters in the Second Half of Life," such a comeback is called an "encore career," in which people find work that provides meaningful and significant contributions to the greater good in the second of half of their lives.

"Instead of freedom from work, they are searching for the freedom to work," Freedman says. "Instead of accepting the notion of a career as an arc that rises in youth, peaks in midlife and declines into retirement, they are charting a new trajectory -- one that for many will reach its apex of meaning and impact when others in past generations headed for the sidelines."

In fact, 5.3 million to 8.4 million people between the ages of 44 and 70 have already launched encore careers, according to a recent MetLife Foundation/Civic Ventures survey. Fifty percent of people of the same age not already engaged in new careers say that they want to be and they want to move into such fields as education, health care, government and nonprofit work.

Don't call it a comeback

Though many workers want to make a transition back to the work force for various reasons, many don't know exactly how to do it. Lots of workers don't know the options they have when they want to come back to work -- or the obstacles they might face.

"Workers returning to the work force should not assume they will be able to pick up where they left off, even those who left recently," says Jennifer Berman, managing director of the HR advisory, consulting and training group at CBIZ Human Capital Services. "Returning workers need an understanding of what industries are hiring for what types of positions. From there, they'll need to conduct an inventory of what skills they possess that are marketable to those opportunities and how they will obtain the skills they may lack."

Many options exist for workers who want to learn fresh skills in a new industry or career. These programs can open doors to full-time work, provide experience in areas that you've previously lacked or allow you to get your feet wet in a new profession before committing to it permanently.

Here are some options available to workers who want to rejoin the work force:

1. Returnship

Returnships are similar to internships, except they are for experienced professionals. They're designed for workers who have left the work force and want to re-enter the corporate world, most commonly in a different line of work than the one they left. A returnship could also be an internship in new field in order to give you the opportunity to test the waters before making a career change.

Several companies, such as Sara Lee Corp. and Goldman Sachs, have already implemented similar programs. Sara Lee, for example, launched the Returnships @ Sara Lee program in October 2008. The initiative was put in place to provide flexible opportunities for midcareer individuals to re-enter the work force after an extended leave. Participants also have the potential for a permanent position after completion of the returnship program.

Brenda C. Barnes, chairwoman and chief executive officer of Sara Lee Corp., says the program "provides a win-win situation for candidates and for our company by offering flexible work arrangements on a trial basis, while at the same time allowing Sara Lee to tap into a deep talent pool of underutilized professionals."

If you have your eyes set on a company and you don't know if it offers a returnship-type program, Berman suggests developing a proposition to create one.

"In these tight times, almost every industry has trimmed staff to a point where there are real needs. Few employers will turn away free labor that offers a real value," she says. "Learn what the organization is missing or needing. Develop a proposal for the services you could provide in exchange for consideration for a future hire, introduction to another business unit or detailed recommendation."

2. VocationVacations

VocationVacations, another type of mini-internship experience, offers clients the chance to test-drive a dream job under the guidance of expert mentors who are passionate about what they do, says Brian Kurth, president of the company. Approximately 20 percent of "vocationers" have either switched full-time careers, gone back to school or have taken the steps to land their dream jobs.

"What better way to return to the work force from early retirement, maternity leave or an extended layoff than to test it all out first?" he asks.

VocationVacations offer one- to three-day, hands-on, career immersion experiences under the guidance of mentors who are experienced in the field in which a "vocationer" is interested. The company offers more than 160 types of vocations in everything from acting to yoga.

Though a VocationVacation is different from a returnship in that you pay to participate, the expense should be thought of as an investment toward your future. After all, you do get a one-on-one mentorship, sound career-coaching advice and other perks. Kurth says some mentors feel so strongly about their vocationers that they've hired them full time. For more information, visit their Web site.

3. Mom Corps

Mom Corps, a staffing solution firm, places women returning to the work force in part-time, permanent, full-time, flexible and contract or project-based work arrangements. Companies such as KPMG, Merrill Lynch, Home Depot and General Electric are able to access a pool of professionals who have opted out of the traditional workplace, but still have the talent and time to take on work.

"By hiring a contract or part-time worker during the economic downturn, companies are able to operate at a lower cost and still see results," says Allison O'Kelley, CEO and founder of Mom Corps.

Unlike a returnship or other options, Mom Corps offers flexible job opportunities suited to candidates' qualifications and scheduling needs. Workers still have the option of returning to the work force, yet don't have to immediately dive in full time. Employers can post jobs, search for candidates and view résumés matching their criteria, and candidates can do the same while looking for companies.

Benefits of return programs

Still not sold on a return program? Here are several benefits to consider:

1. You are essentially able to "try before you buy," Kurth says. Return programs allow workers to determine whether they truly like the field they are entering and if they don't, they have saved themselves a lot of time by not pursuing something they don't enjoy or aren't cut out for.

2. Workers, though unpaid, get experience in a company, which is great for their résumé and networking pool.

3. Employers get free work from seasoned professionals.

4. Return programs give returning workers an opportunity to not only test out an experience, but also obtain additional skills, Berman says.

5. Return programs are instant networking, Kurth says. Everyone you'll work with will know people who know people, etc.